This invention relates generally to ridable bouncing apparatuses and more particularly to such apparatuses which achieve high performance, have radically adjustable spring strength or which employ compound elastomer springs or enclosed thrust assemblies. The invention also relates to ridable bouncing apparatuses that provide convenient engagement and disengagement of springs/tension elements, as well as efficient internal storage of the springs/tension elements. Furthermore, the present invention also relates to torque-transmitting bearings and universal joints for improved performance.
Steel-spring pogo sticks are the dominant form of ridable bouncing apparatus, and forms are known which aspire to high performance or adjustability or which have enclosed springs. High performance (that is, energy storage and return in the kilojoule range) is problematic for steel spring devices because the storage capacity of the material is low: about 80 joules/kilogram. 1000 joules of storage thus requires about 12 kilograms (26 pounds) of spring. An apparatus of such weight would be unwieldy, unappealing and hazardous due to its own momentum. Manufacturers have stopped at about one-third of this level (which still makes for a rather heavy apparatus). A group of engineering students at the Oregon Institute of Technology, however, has produced a pogo stick with a 47-inch custom-made steel spring intended to propel 250 pounds to a height of 5 feet (implying a capacity of 1700 joules, and a spring weight approaching 40 pounds). Their attained height is 18 inches; they express disappointment, and blame the unwieldiness of the design.
No radically-adjustable steel-spring pogo is known, although devices which suggest such a development were discussed as early as 1881. For example, U.S. Pat. No. 438,830 to Yagn in 1890 discloses compound-coil-spring jumping stilts. Several designs which precompress a coil spring to effect a form of adjustability have been presented, for example, in U.S. Pat. No. 238,042 to Herrington in 1881; U.S. Pat. No. 2,793,036 to Hansburg in 1957; and U.S. Pat. No. 3,773,320 to Samiran et al. in 1973. Such pre-compression does not scale the spring (that is, change its strength), and is of little mechanical significance.
Pogo sticks with enclosed coil springs are shown by Hohberger (U.S. Pat. No. 2,712,443 in 1955), Rapaport (U.S. Pat. No. 2,871,016 in 1957) and Gaberson (U.S. Pat. No. 3,116,061 in 1963). Hohberger assembles his molded frame permanently around the coil. Rapaport places a flexible plastic cover around the spring. Gaberson places the spring inside the piston, and adds a frame-attached plunger to compress it. All of these designs are limited by the modest capacity of their steel springs.
Air-spring pogo sticks have achieved commercialization using low-pressure air springs, the air being contained either in a ball-like bladder or in a block of low-density plastic foam. Such devices are successful as children""s novelties but are not well-suited to more demanding applications due to the bulk of the entrapped air column. High pressure air springs are theoretically capable of achieving any desired level of performance, and also hold the promise of straightforward adjustability. Their use in pogo sticks was suggested by Woodall (U.S. Pat. No. 2,865,633 in 1958), who stressed the benefit of adjustability, and others (Bourcier de Carbon in U.S. Pat. No. 2,899,685 in 1959; Guin in U.S. Pat. No. 3,351,342 in 1967). There is, however, a practical problem: the energy stored is present in the form of heat at the bottom of the strokexe2x80x94and due to the relatively large amount of energy and relatively small amount of gas, temperatures of several hundreds of degrees are attained. A leading manufacturer has told me of experiments which ended in dismay when the cylinder became hot enough to burn the jumpers"" legs.
Elastomer-powered pogo designs appear in Gaffney and Weaver (in U.S. Pat. No. 2,783,997 in 1957). Their primary concern was with jumping stilts; their pogo design was minimally modified from a conventional tubular design, and had its rubber mounted externally in two bundles, one on either side of the frame tube. These bundles would have made the upper mount about three inches widexe2x80x94and this unshielded object would rake up and down between the knees and thighs of the jumper on each stroke; if the rider attempted to ride bowlegged to avoid it, his contact with and ability to control the stick (as well as his concentration) would suffer.
Bourcier de Carbon (cited above) shows an elastomer-powered stilt, and appears to be the first in this context to mention that rubber is a more efficient spring material than steel and can provide higher levels of performance. His upper mount is exposed, which is viable for a stilt; he does not show a ridable design.
Hoffmeister (U.S. Pat. No. 3,065,962 in 1962) gives a quantitative statement of the startling superiority of rubber: 18 pounds of steel, he points out, can be replaced by 3.75 ounces of rubber. His mechanical design (which is for jumping stilts), however, is extraordinarily unsafe. He attaches the bottom of the tension spring to the top of the frame tube (rather than the bottom, as shown by Gaffney and Bourcier de Carbon). This results in rod ends projecting past the rider""s knees and moving upward relative to the rider as he lands. A jumper landing in a skier""s tuck position will strike the ends of the piston rods with his chest at up to 11 mph.
Prueitt (U.S. Pat. No. 4,449,256 in 1984) cites the scalability of rubber-band springs as a virtue of his design. The design is for multi-piston jumping stilts with exposed piston-heads.
In the past, it has been difficult to perform adjustments on bouncing apparatuses. For instance, a user might have to take the apparatus completely apart in order to make adjustments to the spring or other tension element. Therefore, it is desirable to provide convenient access to these and other components that are inside the bouncing apparatus.
Furthermore, a need exists for a relatively large disk foot for use in high-performance pogo sticks. Two university projects have striven for record-setting pogo performance, and both have adopted disk feet. The developers of the BowGo at Carnegie Mellon University have used a disk rigidly mounted on the piston, with a convex rubber pad on the bottom. While this system may permit the BowGo to be used on a lawn, it does little to accommodate uneven ground or tilting of the pogo, and does not distribute the load uniformly over the surface of the disk. A project at the Oregon Institute of Technology has employed a disk foot mounted on a ball joint. While such, a system may provide adequate pressure distribution and can accommodate pogo tilts and uneven ground, the ball joint permits the foot to rotate relative to the shaft. Thus, it has little capacity to transmit torque, and will not enable aggressive yaw maneuvers such as, e.g., aerial spins.
Therefore, there is a need for a bouncing apparatus capable of unprecedented performance.
There is also a need for a bouncing apparatus having a thrust function that can be scaled to match the weights and inclinations of a broad range of rider sizes, thus affording each rider an optimal apparatus that exploits the travel available in its linkage.
There is also a need for a bouncing apparatus that shields the rider from the moving parts of the apparatus during operation, but permits convenient access to tension elements for adjustment of spring strength.
There is also a need for a bouncing apparatus having a foot that is capable of tilting in any direction without rotating, and that can be used on soft surfaces such as lawns, and that can offer improved traction on hard surfaces.
There is also a need for a bouncing apparatus with a spring that can conveniently be pre-tensioned for use and relaxed for storage.
There is also a need for a bouncing apparatus having a cartridge unit structure that permits convenient removal from the apparatus to allow a user to perform adjustments on tension elements or other components.
Furthermore, there is also a need for a bearing that can transmit torque, so that torque exerted by a rider on the assembly does not cause the carriage to rotate around the piston but rather transmits the torque to the piston.
The invention provides a ridable bouncing apparatus which has great energy-storage capacity, and whose thrust function is radically scalable to suit the weights and inclinations of a variety of riders. These benefits are achieved through the use of a compound tension spring, and a set of innovations extending to all components of the system which permit the potential benefits of such a spring to be safely and conveniently realized.
The ridable bouncing apparatus includes a carriage assembly that can support a person; a foot alternately retracting toward and extending away from the carriage assembly; and a thrust assembly. The thrust assembly is mounted to the carriage assembly and to the foot and has a force that impels the extension and resists the retraction. The bouncing apparatus includes a shield member protecting the person from contact with at least a portion of the thrust assembly. The thrust assembly has at least one tension element that supplies a tension force. The bouncing apparatus has an access feature that enables engagement and disengagement of the tension element.
The tension assembly preferably includes a linkage and a spring, with the linkage connecting the foot to the carriage assembly and limiting the motion of the foot to a single linear trajectory, motion along which is either retraction or extension, and with the spring acting on the linkage to impel the extension and resist the retraction. The spring preferably includes a set of elongated elastomeric elements, and is scaled by adding or removing individual elements to or from the operative set. The access features are provided to make this operation convenient. In some embodiments these features are apertures which permit spring elements to be physically added to or removed from the apparatus; in some cases doors are provided to cover such apertures during operation. Other embodiments include mechanisms which permit switching of individual spring elements between engaged and disengaged states but leave disengaged elements mounted on the apparatus.
The foot is preferably a relatively large foot mounted on a universal joint, provided both to permit adequate traction when the apparatus is tilted and to reduce ground loading. This reduces the potential for damage to floors and permits use on relatively soft ground such as lawns. The foot preferably includes a gripping surface that provides improved frictional contact with the bouncing surface, e.g., the ground. The gripping surface may comprise a plurality of layers to further reduce the shock of impact when the foot contacts the ground.
A shield requirement exists because the mounts for the spring can be bulky and at least one of them must move quickly, relative to the carriage. The requirement can be met by replacing the conventional slender tube frame with a much larger hollow column whose interior serves as an enclosed channel for the upper mount.
The thrust assembly can include a piston, alternately retracting upwardly toward and extending downwardly away from the carriage assembly, with the foot at a distal end. The thrust assembly can further include at least one bearing, mounted between the carriage assembly and the piston, for easing the retraction and extension and for limiting lateral movement of the piston relative to the carriage assembly. The thrust assembly can further include a set of tension elements mounted to the carriage assembly and to the piston, thereby impelling the extension and resisting the retraction. Preferably, each tension element is mounted so as to permit it to be easily attached to or detached from at least one attachment point, to add it to or remove it from (as applicable) a set of operative tension elements.
Further in those and other embodiments, the access feature can include the channel, when the channel is adapted to enable disengagement and engagement of the tension element by, for example, allowing immediate access to the tension element for adjustment of the tension force. In this regard, the frame can have a panel that can be displaced to allow the immediate access. The access feature can also further include upper and lower mounts within the channel, to which each tension element can be mounted, each of the mounts having an opening through which ends of the tension elements can be passed. The rider can therefore displace the panel and reduce the tension force by removing (disengaging) at least one tension element. Similarly, the rider can displace the panel and increase the tension force by adding (engaging) another tension element, or replacing a previously removed (previously disengaged) tension element. In this regard, each tension element can be individually mountable and demountable.
In other embodiments, the access feature can include an assembly that mechanically engages and disengages tension elements. In such embodiments, it is preferable that the tension elements are not bundled and that the mounts are not bulky. While any suitable mechanism can be used, a preferred embodiment includes snags which have suitable control features at a location accessible by the rider. The snags can be operated by means of the control features to catch hold of a fixture attached to the end of each tension element. Also preferably, a storage rack can be used/ to put the fixtures of the disengaged tension elements precisely where the snags need them to be when the piston is arrested. The rack can be attached to the piston. Accordingly, disengaged elements remain stretched between the rack and the upper mount, with some tension keeping them snug, and travel up and down with the piston. Preferably, the ends of the tension elements are provided with snaggable fixtures that seat up against the storage rack when the elements are disengaged.
In alternative embodiments, the access feature may comprise one or more slots in the frame of the apparatus. The slots may permit a finger or tool to penetrate into the frame and engage or disengage a tension element. The tension element can be disengaged and remain within the frame. The tool may employ direct force, leverage or another force to engage or disengage a tension element.
In accordance with an embodiment of the present invention, a bouncing apparatus is provided having a carriage assembly, a foot, a thrust assembly and a universal joint. The carriage assembly can support a person. The foot alternatively retracts towards and extends from the carriage assembly. The thrust assembly is mounted to the carriage assembly and the foot. The thrust assembly effects extension and retraction of the foot. The universal joint connects the foot and the thrust assembly.
In accordance with another embodiment of the present invention, a bouncing apparatus is provided comprising a carriage assembly, a foot, a piston and a plurality of tension elements. The carriage assembly can support a user, and includes an exterior shell. The exterior shell defines an interior chamber and enables access to the chamber. The foot is operable to extend away from and retract toward the carriage assembly. The piston effects extension and resists retraction of the foot. The piston connects the foot and the carriage assembly. At least a portion of the piston is within the interior chamber. The plurality of tension elements are in operative contact with the piston, and are contained within the interior chamber. At least some of the plurality of tension elements are individually mountable in an operative state and demountable in an inoperative state with respect to the piston. When a first tension element of the plurality is demounted, the first tension element is stored within the interior chamber.
In accordance with yet another embodiment of the present invention, a bouncing system is provided. The bouncing system comprises a carriage assembly, a foot, a piston, a plurality of tension elements and a tool. The carriage assembly can support a user, and includes an exterior shell. The exterior shell defines an interior chamber and includes an aperture for access to the chamber. The foot is operable to extend away from and retract toward the carriage assembly. The piston connects the foot and the carriage assembly. At least a portion of the piston is within the interior chamber. The plurality of tension elements are in operative contact with the piston, and are contained within the interior chamber. At least some of the plurality of tension elements are individually mountable in an operative state and demountable in an inoperative state with respect to the piston. When a first tension element of the plurality is demounted, the first tension element is stored within the interior chamber. The tool is for mounting and demounting at least some of the plurality of tension elements. The tool includes a handle and an operative portion remote from the handle. The operative portion is capable of being passed through the aperture to effect mounting and demounting.
In accordance with another embodiment of the present invention, a bouncing apparatus is provided comprising a carriage assembly, a foot, a piston and a plurality of tension elements. The carriage assembly can support a user, and has an exterior shell defining an interior chamber. The exterior shell includes an aperture for access to the interior chamber. The foot is operable to extend away from and retract toward the carriage assembly. The piston connects the foot and the carriage assembly. At least a portion of the piston is within the interior chamber. The plurality of tension elements are in operative contact with the piston, and are contained within the interior chamber. At least a first one of the plurality is individually mountable in an operative state and demountable in an inoperative state with respect to the piston. The first one of the plurality includes a hanger for mounting, wherein the user can mount and demount the first tension element by contacting the hanger through the aperture. When the first tension element is demounted, it is stored within the interior chamber.
In accordance with yet another embodiment, a bouncing apparatus comprises a carriage assembly and a cartridge. The carriage assembly has an exterior shell defining an interior chamber. The cartridge is insertible into the interior chamber. The cartridge includes a tension element, a first mount and a second mount. The tension element has first and second ends. The first mount is operable to connect to the first end. The second mount is operable to connect to the second end.
In accordance with another embodiment, a bouncing apparatus comprising a carriage assembly, a piston and a torque-transmitting bearing is provided. The carriage assembly can support a user, and has an exterior shell defining an interior chamber. The piston is slidably associated with the carriage assembly. The torque-transmitting bearing is disposed between the piston and the carriage assembly such that the torque-transmitting bearing permits extension and retraction of the piston, but resists rotation of the piston relative to the carriage assembly.
In accordance with yet another embodiment, a bouncing apparatus comprising a carriage assembly, a foot, a piston, a plurality of tension elements and a torque-transmitting bearing is provided. The carriage assembly can support a user, and has an exterior shell defining an interior chamber. The foot is operable to extend away from and retract toward the carriage assembly. The piston connects the foot and the carriage assembly. The plurality of tension elements is within the interior chamber and mount to the carriage assembly and to the piston. The plurality of tension elements are operable to impel extension and resist retraction. The torque-transmitting bearing is disposed between the piston and the carriage assembly such that the torque-transmitting bearing resists rotation of the piston relative to the carriage assembly.